In some applications, there may be a need to determine, in an accurate way, pressure values over rather extensive regions, the surface of which may be of the order of square centimeters or square meters. For example, in some fluidic filters, it is useful to have a measurement of the pressure exerted by the fluid that is treated in order to monitor the operating conditions of the fluid itself. In a different field, the use of pressure sensors incorporated in the innersole of footwear enables data to be obtained regarding the distribution of the weight of the user on the sole of his foot, both for clinical assessments (evaluation and correction of posture and gait) and for other purposes that may be of interest for the user (for example, for providing a pedometer function).
When there are requirements of this sort, usually an array of independent point sensors is employed, which provides information on the pressure exerted in a given and limited area. However, such approaches of this type may not always satisfactory. In many cases, in fact, positioning of discrete sensors is problematical, if not impossible, and in any case more often than not there is the problem of the wired connection with the detection circuitry. In some cases, as in the case of fluidic filters, the very presence of the sensors may cause unacceptable disturbance.